Echocardiography was used 1) to assess the prevalance and type of cardiac abnormalities occurring in subjects with mild-to-moderate essential hypertension, 2) to examine the relation of the echocardiographic findings to severity of hypertension and 3) to compare the relative sensitivity of this technique with the standard 12-lead electrocardiogram and the routine chest X-ray for detecting cardiac abnormalities in such subjects. Our findings demonstrate a high prevalence of cardiac abnormalities in a population of asymptomatic hypertensive subjects. Moreover, these abnormalities can be detected by echocardiography before they are otherwise apparent.